Вправи 201 - 300 » 212 (8-12)

8) 7/2ab : 14/4a = 7/2ab • 4a/14 = (7 •4a)/(2ab •14) = 1/b; 9) 6x/5 : 12y/25 = 6x/5 • 25/12y = (6x •25)/(5 •12y) = 5x/2y; 10) 7/3a : 28/9b = 7/3a • 9b/28 = (7 •9b)/(3a •28) = 3b/4a; 11) 3x/8y : 21/40xy = 3x/8y • 40xy/21 = (3x •40xy)/(8y •21) = 〖5x〗^2/7; 12) 9/2ab : 63/16b = 9/2ab • 16b/63 = (9 •16b)/(2ab •63) = 8/7a.